As others pointed out lready, others did it, too.
Audi has a mild-hybrid 48V (as do many others) that also runs some other things like active roll control and the power steering pump.
They still have a 12v system running infotainment, seat heaters, defrosters, powered seats, lights, etc. etc.
The move to 48V means much less power is lost (power loss = (IxI)xR ), cables can be much smaller, cables and terminals can be much lighter and much less copper can be used used.
Basically it's just a more efficient way of doing things.